content: /* Copyright (C) 2016-2018 Alibaba Group Holding Limited
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
      http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  
  // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  package com.google.protobuf;
  
  import java.io.IOException;
  import java.util.Arrays;
  
  /**
   * {@code UnknownFieldSetLite} is used to keep track of fields which were seen
   * when parsing a protocol message but whose field numbers or types are
   * unrecognized. This most frequently occurs when new fields are added to a
   * message type and then messages containing those fields are read by old
   * software that was compiled before the new types were added.
   *
   * <p>For use by generated code only.
   *
   * @author dweis@google.com (Daniel Weis)
   */
  public final class UnknownFieldSetLite {
    
    // Arbitrarily chosen.
    // TODO(dweis): Tune this number?
    private static final int MIN_CAPACITY = 8;
  
    private static final UnknownFieldSetLite DEFAULT_INSTANCE =
        new UnknownFieldSetLite(0, new int[0], new Object[0], false /* isMutable */);
  
    /**
     * Get an empty {@code UnknownFieldSetLite}.
     *
     * <p>For use by generated code only.
     */
    public static UnknownFieldSetLite getDefaultInstance() {
      return DEFAULT_INSTANCE;
    }
    
    /**
     * Returns a new mutable instance.
     */
    static UnknownFieldSetLite newInstance() {
      return new UnknownFieldSetLite();
    }
  
    /**
     * Returns a mutable {@code UnknownFieldSetLite} that is the composite of {@code first} and
     * {@code second}.
     */
    static UnknownFieldSetLite mutableCopyOf(UnknownFieldSetLite first, UnknownFieldSetLite second) {
      int count = first.count + second.count;
      int[] tags = Arrays.copyOf(first.tags, count);
      System.arraycopy(second.tags, 0, tags, first.count, second.count);
      Object[] objects = Arrays.copyOf(first.objects, count);
      System.arraycopy(second.objects, 0, objects, first.count, second.count);
      return new UnknownFieldSetLite(count, tags, objects, true /* isMutable */);
    }
  
    /**
     * The number of elements in the set.
     */
    private int count;
    
    /**
     * The tag numbers for the elements in the set.
     */
    private int[] tags;
    
    /**
     * The boxed values of the elements in the set.
     */
    private Object[] objects;
    
    /**
     * The lazily computed serialized size of the set.
     */
    private int memoizedSerializedSize = -1;
    
    /**
     * Indicates that this object is mutable. 
     */
    private boolean isMutable;
  
    /**
     * Constructs a mutable {@code UnknownFieldSetLite}.
     */
    private UnknownFieldSetLite() {
      this(0, new int[MIN_CAPACITY], new Object[MIN_CAPACITY], true /* isMutable */);
    }
    
    /**
     * Constructs the {@code UnknownFieldSetLite}.
     */
    private UnknownFieldSetLite(int count, int[] tags, Object[] objects, boolean isMutable) {
      this.count = count;
      this.tags = tags;
      this.objects = objects;
      this.isMutable = isMutable;
    }
    
    /**
     * Marks this object as immutable.
     * 
     * <p>Future calls to methods that attempt to modify this object will throw.
     */
    public void makeImmutable() {
      this.isMutable = false;
    }
    
    /**
     * Throws an {@link UnsupportedOperationException} if immutable.
     */
    void checkMutable() {
      if (!isMutable) {
        throw new UnsupportedOperationException(); 
      }
    }
  
    /**
     * Serializes the set and writes it to {@code output}.
     *
     * <p>For use by generated code only.
     */
    public void writeTo(CodedOutputStream output) throws IOException {
      for (int i = 0; i < count; i++) {
        int tag = tags[i];
        int fieldNumber = WireFormat.getTagFieldNumber(tag);
        switch (WireFormat.getTagWireType(tag)) {
          case WireFormat.WIRETYPE_VARINT:
            output.writeUInt64(fieldNumber, (Long) objects[i]);
            break;
          case WireFormat.WIRETYPE_FIXED32:
            output.writeFixed32(fieldNumber, (Integer) objects[i]);
            break;
          case WireFormat.WIRETYPE_FIXED64:
            output.writeFixed64(fieldNumber, (Long) objects[i]);
            break;
          case WireFormat.WIRETYPE_LENGTH_DELIMITED:
            output.writeBytes(fieldNumber, (ByteString) objects[i]);
            break;
          case WireFormat.WIRETYPE_START_GROUP:
            output.writeTag(fieldNumber, WireFormat.WIRETYPE_START_GROUP);
            ((UnknownFieldSetLite) objects[i]).writeTo(output);
            output.writeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP);
            break;
          default:
            throw InvalidProtocolBufferException.invalidWireType();
        }
      }
    }
  
    /**
     * Serializes the set and writes it to {@code output} using {@code MessageSet} wire format.
     *
     * <p>For use by generated code only.
     */
    public void writeAsMessageSetTo(CodedOutputStream output) throws IOException {
      for (int i = 0; i < count; i++) {
        int fieldNumber = WireFormat.getTagFieldNumber(tags[i]);
        output.writeRawMessageSetExtension(fieldNumber, (ByteString) objects[i]);
      }
    }
  
  
    /**
     * Get the number of bytes required to encode this field, including field number, using {@code
     * MessageSet} wire format.
     */
    public int getSerializedSizeAsMessageSet() {
      int size = memoizedSerializedSize;
      if (size != -1) {
        return size;
      }
      
      size = 0;
      for (int i = 0; i < count; i++) {
        int tag = tags[i];
        int fieldNumber = WireFormat.getTagFieldNumber(tag);
        size += CodedOutputStream.computeRawMessageSetExtensionSize(
            fieldNumber, (ByteString) objects[i]);
      }
      
      memoizedSerializedSize = size;
      
      return size;
    }
  
    /**
     * Get the number of bytes required to encode this set.
     *
     * <p>For use by generated code only.
     */
    public int getSerializedSize() {
      int size = memoizedSerializedSize;
      if (size != -1) {
        return size;
      }
      
      size = 0;
      for (int i = 0; i < count; i++) {
        int tag = tags[i];
        int fieldNumber = WireFormat.getTagFieldNumber(tag);
        switch (WireFormat.getTagWireType(tag)) {
          case WireFormat.WIRETYPE_VARINT:
            size += CodedOutputStream.computeUInt64Size(fieldNumber, (Long) objects[i]);
            break;
          case WireFormat.WIRETYPE_FIXED32:
            size += CodedOutputStream.computeFixed32Size(fieldNumber, (Integer) objects[i]);
            break;
          case WireFormat.WIRETYPE_FIXED64:
            size += CodedOutputStream.computeFixed64Size(fieldNumber, (Long) objects[i]);
            break;
          case WireFormat.WIRETYPE_LENGTH_DELIMITED:
            size += CodedOutputStream.computeBytesSize(fieldNumber, (ByteString) objects[i]);
            break;
          case WireFormat.WIRETYPE_START_GROUP:
            size +=  CodedOutputStream.computeTagSize(fieldNumber) * 2
                + ((UnknownFieldSetLite) objects[i]).getSerializedSize();
            break;
          default:
            throw new IllegalStateException(InvalidProtocolBufferException.invalidWireType());
        }
      }
      
      memoizedSerializedSize = size;
      
      return size;
    }
    
    private static boolean equals(int[] tags1, int[] tags2, int count) {
      for (int i = 0; i < count; ++i) {
        if (tags1[i] != tags2[i]) {
          return false;
        }
      }
      return true;
    }
  
    private static boolean equals(Object[] objects1, Object[] objects2, int count) {
      for (int i = 0; i < count; ++i) {
        if (!objects1[i].equals(objects2[i])) {
          return false;
        }
      }
      return true;
    }
  
    @Override
    public boolean equals(Object obj) {
      if (this == obj) {
        return true;
      }
  
      if (obj == null) {
        return false;
      }
  
      if (!(obj instanceof UnknownFieldSetLite)) {
        return false;
      }
      
      UnknownFieldSetLite other = (UnknownFieldSetLite) obj;    
      if (count != other.count
          || !equals(tags, other.tags, count)
          || !equals(objects, other.objects, count)) {
        return false;
      }
  
      return true;
    }
  
    @Override
    public int hashCode() {
      int hashCode = 17;
      
      hashCode = 31 * hashCode + count;
      hashCode = 31 * hashCode + Arrays.hashCode(tags);
      hashCode = 31 * hashCode + Arrays.deepHashCode(objects);
      
      return hashCode;
    }
  
    /**
     * Prints a String representation of the unknown field set.
     *
     * <p>For use by generated code only.
     *
     * @param buffer the buffer to write to
     * @param indent the number of spaces the fields should be indented by
     */
    final void printWithIndent(StringBuilder buffer, int indent) {
      for (int i = 0; i < count; i++) {
        int fieldNumber = WireFormat.getTagFieldNumber(tags[i]);
        MessageLiteToString.printField(buffer, indent, String.valueOf(fieldNumber), objects[i]);
      }
    }
  
    // Package private for unsafe experimental runtime.
    void storeField(int tag, Object value) {
      checkMutable();
      ensureCapacity();
      
      tags[count] = tag;
      objects[count] = value;
      count++;
    }
    
    /**
     * Ensures that our arrays are long enough to store more metadata.
     */
    private void ensureCapacity() {
      if (count == tags.length) {        
        int increment = count < (MIN_CAPACITY / 2) ? MIN_CAPACITY : count >> 1;
        int newLength = count + increment;
          
        tags = Arrays.copyOf(tags, newLength);
        objects = Arrays.copyOf(objects, newLength);
      }
    }
    
    /**
     * Parse a single field from {@code input} and merge it into this set.
     *
     * <p>For use by generated code only.
     *
     * @param tag The field's tag number, which was already parsed.
     * @return {@code false} if the tag is an end group tag.
     */
    boolean mergeFieldFrom(final int tag, final CodedInputStream input) throws IOException {
      checkMutable();
      final int fieldNumber = WireFormat.getTagFieldNumber(tag);
      switch (WireFormat.getTagWireType(tag)) {
        case WireFormat.WIRETYPE_VARINT:
          storeField(tag, input.readInt64());
          return true;
        case WireFormat.WIRETYPE_FIXED32:
          storeField(tag, input.readFixed32());
          return true;
        case WireFormat.WIRETYPE_FIXED64:
          storeField(tag, input.readFixed64());
          return true;
        case WireFormat.WIRETYPE_LENGTH_DELIMITED:
          storeField(tag, input.readBytes());
          return true;
        case WireFormat.WIRETYPE_START_GROUP:
          final UnknownFieldSetLite subFieldSet = new UnknownFieldSetLite();
          subFieldSet.mergeFrom(input);
          input.checkLastTagWas(
              WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP));
          storeField(tag, subFieldSet);
          return true;
        case WireFormat.WIRETYPE_END_GROUP:
          return false;
        default:
          throw InvalidProtocolBufferException.invalidWireType();
      }
    }
  
    /**
     * Convenience method for merging a new field containing a single varint
     * value. This is used in particular when an unknown enum value is
     * encountered.
     *
     * <p>For use by generated code only.
     */
    UnknownFieldSetLite mergeVarintField(int fieldNumber, int value) {
      checkMutable();
      if (fieldNumber == 0) {
        throw new IllegalArgumentException("Zero is not a valid field number.");
      }
  
      storeField(WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_VARINT), (long) value);
      
      return this;
    }
  
    /**
     * Convenience method for merging a length-delimited field.
     *
     * <p>For use by generated code only.
     */
    UnknownFieldSetLite mergeLengthDelimitedField(final int fieldNumber, final ByteString value) {  
      checkMutable();
      if (fieldNumber == 0) {
        throw new IllegalArgumentException("Zero is not a valid field number.");
      }
  
      storeField(WireFormat.makeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED), value);
      
      return this;
    }
    
    /**
     * Parse an entire message from {@code input} and merge its fields into
     * this set.
     */
    private UnknownFieldSetLite mergeFrom(final CodedInputStream input) throws IOException {
      // Ensures initialization in mergeFieldFrom.
      while (true) {
        final int tag = input.readTag();
        if (tag == 0 || !mergeFieldFrom(tag, input)) {
          break;
        }
      }
      return this;
    }
  }
  